basic

Reaction Order from Initial-Rate Doubling-of-Concentration Experiment Calculator

order = log(rate₂/rate₁) / log([A]₂/[A]₁).

Determine the order of a reaction with respect to a reactant A from two initial-rate experiments where [A] is changed (typically doubled) and all other concentrations are held constant. Order = log(rate₂ / rate₁) / log([A]₂ / [A]₁). Integer-rounded result is the most likely true order. Doubling [A] and observing a 4× rate jump ⇒ second order; 2× ⇒ first; no change ⇒ zero.

Dr. Helena Ortiz By Dr. Helena Ortiz
Published Last reviewed 1 min read

Inputs

mol L⁻¹ s⁻¹
mol L⁻¹ s⁻¹
mol/L
mol/L

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

n = log(rate₂/rate₁) / log([A]₂/[A]₁).

In depth

Determine the order of a reaction with respect to a reactant A from two initial-rate experiments where [A] is changed (typically doubled) and all other concentrations are held constant. Order = log(rate₂ / rate₁) / log([A]₂ / [A]₁). Integer-rounded result is the most likely true order. Doubling [A] and observing a 4× rate jump ⇒ second order; 2× ⇒ first; no change ⇒ zero.